EAGER: CAS-MNP: Understanding the Dispersibility of Aging Micro/Nanoplastics

该奖项由美国国家科学基金会化学部颁发，支持路易斯安那州立大学的Bhuvnesh Bharti教授和Kalliat T. Valsaraj教授研究微/纳米塑料。由于废弃塑料废物的逐渐老化和风化，微/纳米塑料在环境中变得非常普遍。它们可以向食物链上游移动，并可能影响水生和陆生物种。为了评估微/纳米塑料的潜在健康风险，了解它们如何与水环境相互作用至关重要。该团队研究了微/纳米塑料在阳光诱导下氧化和老化的影响，这增加了它们的润湿性和在水中分散的能力。该项目是有风险的探索性项目，但所获得的知识有助于指导未来对微塑料的环境运输和命运的深入研究。该项目为研究生提供了在新兴领域发展新技能的机会，并积极吸引来自巴吞鲁日社区学院的本科生参与拟议的研究。这个项目解决了这样一个问题：微/纳米塑料是作为微或纳米大小的颗粒存在，还是它们聚集成更大的结构？这个问题至关重要，因为微/纳米塑料对生物、环境和大气的任何影响都将由它们的分散/聚集状态决定。光氧化过程导致降解聚合物表面形成亲水的化学官能团，这增加了微/纳米塑料的水润湿性和分散性。该团队研究了光氧化和溶剂pH/离子强度对由聚乙烯、聚丙烯和聚苯乙烯制成的球形微/纳米塑料模型分散性的影响。这些模型塑料在受控的实验室条件下被光氧化，并使用小角度散射、光学显微镜和光谱技术的组合来表征它们的分散状态。这对于了解微/纳米塑料通过掺入雾、烟雾和薄雾等含水气溶胶液滴进入大气的可能性非常重要。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This award from the NSF Chemistry Division supports Professor Bhuvnesh Bharti and Professor Kalliat T. Valsaraj of Louisiana State University to study micro/nanoplastics. Micro/nanoplastics have become very common in the environment because of the gradual aging and weathering of discarded plastic waste. They can move up the food chain and potentially impact both aquatic and terrestrial species. In order to assess the potential health risks of micro/nanoplastics, it is critical to understand how they interact with an aqueous environment. The team studies the effect of sunlight-induced oxidation and aging of micro/nanoplastics which increases their wettability and ability to disperse in water. This project is exploratory with risk but the knowledge gained helps guide future in-depth studies of the environmental transport and fate of microplastics. The project provides opportunities for graduate students to develop new skills in an emerging field and actively engages undergraduate students from Baton Rouge Community College in the proposed research. This project addresses the question: Do micro/nanoplastics exist as micro or nanosized particles or do they aggregate into larger structures? This question is critical because any biological, environmental, and atmospheric impact of the micro/nanoplastics will be governed by their dispersed/aggregated state. Photooxidation processes lead to the formation of hydrophilic chemical functional groups on the surface of a degrading polymer, which increases the water wettability and dispersibility of the micro/nanoplastics. The team investigates the effect of photooxidation and solvent pH/ionic strength on the dispersibility of spherical shaped model micro/nanoplastics made from polyethylene, polypropylene, and polystyrene. These model plastics are photooxidized under controlled laboratory conditions and characterized for their dispersed state using a combination of small angle scattering, light microscopy, and spectroscopic techniques. This is important for understanding the potential of micro/nanoplastics to be transported into the atmosphere by incorporation into aqueous aerosol droplets such as fog, smog, and mist.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.